1. Field of the Invention
The invention relates in general to seat actuators and locks and in particular to electrically actuated actuators and locks as used in adjustable airline seating.
2. Description of the Prior Art
The seat backs and foot rests of airline seats are typically adjustable by the user through a range of positions. The user expects to adjust various elements of the airline seat in a smoothed, damped and completely arbitrarily adjustable position. The user has come to expect that a portion of the seat, such as the seat back, can be positioned at any point within a certain range by activation of a single control and then securely locked in the arbitrarily selected position by release of the control.
Furthermore, the purchaser of such airline seating expects that the mechanisms through which such seat adjustments are provided not only operate smoothly in the manner expected by the user, but must be extremely reliable and arbitrarily adjustable by airline service personnel. Airline seating frames are expected to operate largely trouble free with heavy use through their entire 10-20 year lifetime. In other words, the airline expects a single seat actuator mechanism to be usable and adjustable in all of the seats of the airplane.
For example, some seats, such as those in first class, have a greater pitch or spacing which allows inclination of the seat back to a greater degree. On the other hand, the pitch or longitudinal spacing of tourist or business class seating is less and inclination of the seat back must be somewhat more limited in order to avoid interference between adjacent passengers. Still further, some seats are situated next to bulkheads, exits or emergency exits and must similarly be restricted in their movement by virtue of available space or safety regulations. A single adjustable mechanism must be provided for each of these conditions in addition to meeting all the other requirements and expectations of the user.
The simplest prior art locking and actuating seat mechanism is a mechanical mechanism such as commonly used in passenger automobiles. Typically, these mechanical mechanisms are not damped, but are spring loaded and can be adjusted only into one of a discrete plurality of positions. Such mechanical mechanisms are also traditionally less reliable and more difficult to operate.
Mechanical activating locking mechanisms are also found in airline seats. Typically, the locking mechanism may be a separate element from the adjusting mechanism or may be combined in a single unit which is hydraulically actuated. Many such prior mechanisms are manually activated in that the portion of the seat which is to be adjusted is manually forced into the desired position while the locking mechanism is released. The locking mechanism is actuated and the seat is then left in the last manually adjusted position.
However, users of preferred airline services have come to expect or appreciate automatic or electrically actuated seat adjustment mechanisms, but still demand the control features typical of prior art hydraulic locking mechanisms.
One prior art methodology used to supply this need is to provide an electrical actuator which moves the seat part in combination with a conventional hydraulic locking mechanism. The electrical actuator and hydraulic lock are then cross-coupled through a single control through a series of linkages and cables to effect the desired operation. However, the complexity of operation of such a combination compromises its reliability, its cost is increased and field service installation and adjustment of multiple cables and complex linkages becomes problematic.
Therefore, what is needed is an electrically actuated seat mechanism which includes both adjustment and locking functions within a single mechanism.